1. The IPO Model
Input – Process - Output

2. I = Input
 Input is something from the external
environment that is fed into the system.
 In an information system, the inputs may
be raw data "captured" in some way or
pre-existing data which has been provided
by an external system.
 In either case, the data input is provided
by an external entity.

3. P = Process
 The transformation process is the most
important element of a system.
 The process accepts the inputs into the system
and performs some type of operation on it which
transforms it into some other state. In the
simplest of terms, the process is at the heart of
any system.
 In a computerised information system, the
process is normally the storage, retrieval and
modification of data which is accomplished by
hardware and software.

4. O = Output
 Output from the system which is the result of
processing the input.
 Without output, a system has no link back into
it's external environment.
 Output of an information system may be reports
generated by an information system, or a picture
on a computer monitor, or even data that is fed
into another external system.

5. The IPO Model
Data and
INPUT OUTPU
Processing
T
Your analysis
starts here
The requirements of the Output, more than anything
else, will determine the requirements of the System.

6. Steps to complete an IPO
Model
Steps
1. Read and understand the problem
2. Identify the outputs
 Pick intrinsic variable names that represent the output
3. Decide what data (the inputs) is required in order to
get the required output
 Sometimes these will be given to you, sometimes not,
which means you may need to invent inputs.
4. Once you have the outputs and the inputs you need
to determine how the inputs can be transformed into
the required outputs. This is a dynamic process
which may mean you need to continually return to
the previous steps.

7. Example
Analysis for CelsiusToFahrenheit Program:
 Input
degrees Celsius
 Process
F = C * 9/5 + 32
 Output
degrees Fahrenheit

8. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is worth
15%, the final is worth 30%, and the
projects are worth a total of 40% (10%
each). Given a student's grades for all of
these assignments, calculate the final
score.
What output/s are require?

9. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is worth
15%, the final is worth 30%, and the
projects are worth a total of 40% (10%
each). Given a student's grades for all of
these assignments, calculate the final
score.
What input/s are require?

10. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is worth
15%, the final is worth 30%, and the
projects are worth a total of 40% (10%
each). Given a student's grades for all of
these assignments, calculate the final
score.
What process/es are require?

11. Problem Statement
A student's final grade for a course is a weighted average of two tests, a final
exam, and four projects. Each test is worth 15%, the final is worth 30%, and the
projects are worth a total of 40% (10% each). Given a student's grades for all of
these assignments, calculate the final score.
Input Process Output
Get Result of Test1 1. Calculate FinalScore FinalScore
Get Result of Test2 2. FinalScore = (Test1 + Test2)
Get Result of FinalExam * 15/100 + Test3 * 30/100 +
(Project1 + Project2 +
Get Result of Project1
Project3 + Project4) * 40/100
Get Result of Project2
Get Result of Project3
Get Result of Project4

12. Design Exercises
1. Consider a student file that contains the following data fields:
First Name Last Name Course Grade
Would this set of data be suitable and sufficient to use to test each of the
following programs? Explain why or why not.
 A program that prints a list of SDD students
 A program that prints a list of students nearly failing - those with a grade is less than 50%
 A program that prints a list of student on the Principal’s list
 A program that prints a list of students from Parramatta
 A program that prints a list of female students.
2. Construct an IPO chart for a program that gives an employee
$50 bonus for every 500 items sold in a week.
3. Construct an IPO chart for a program that will output a
student's grading based on letter grades (A, B, C, D, or F) in five
courses.

13. 2 * IPO Examples
Input Processing Output
original number 1. calculate the squared value by multiplying the original number by squared value
itself
2. display the squared value
Input Processing Output
state1 sales 1. enter state1 sales, state2 sales, and commission rate commission
state2 sales 2. calculate the total commission by adding the state1 sales to the state2
commission rate sales, and then multiplying the result by the commission rate
3. display the total commission
Describe what these two IPO models
are doing…

14. 2 more IPO Examples
Input Processing Output
Sales 1. Enter the sales and Commission rate Commission Rate
Commission rate 2. Calculate the commission rate by multiplying sales time Commission
rate
3. Display the Commission rate
Input Processing Output
Original number 1.Enter the Original Number Squared value
2.If the original number is less than or equal to zero then display an error
message, otherwise calculate the squared value by multiplying the Original
number by itself.
3. Display the squared value
Describe what these two IPO models
are doing…